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Re: [BKARTS] Alum in Paper



Well, James,

If the alum reacts to form a new compound, it probably doesn't have the same
properties, and if the excess which has not reacted and is removed by
rinsing, then maybe that's the end of that.

Interesting.

Thanks for your reply.

Signa

-----Original Message-----
From: Book_Arts-L [mailto:BOOK_ARTS-L@xxxxxxxxxxxxxxxx]On Behalf Of
james tapley
Sent: Wednesday, September 14, 2005 1:35 PM
To: BOOK_ARTS-L@xxxxxxxxxxxxxxxx
Subject: Alum in Paper


Wow Signa, this can be a can of worms! In marbling we need to
remember that the alum fixes the color by reacting to form an
insoluble salt. In theory alum that has not reacted is removed by
rinsing after marbling.
Fiber people will have a contribution to make here for their use of
alum as a mordant.
Having said this there are some who believe that the alum actually
can be advantageous to the paper. You might join then check the
archives of the Yahoo marbling group at
http://groups.yahoo.com/group/Marbling/ for a more full discussion of
this.
The alum alone is a very weak acid; it seems to be true that it is
seriously harmful as part of a reaction involving chlorides left over
from pulp bleaching. To a lesser degree other chemical residues may
also react with the alum to produce deleterious effects. It is simply
true that the reaction mechanisms are not fully understood.
Best, James

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Edelpappband / "Millimeter" Binding Bind-O-Rama, Entry Deadline - October 1,
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             ***********************************************
Edelpappband / "Millimeter" Binding Bind-O-Rama, Entry Deadline - October 1, 2005
                                    
             For all your subscription questions, go to the
                      Book_Arts-L FAQ and Archive.
                                    
          See <http://www.philobiblon.com> for full information
             ***********************************************


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